Lack of Power/Lack of Boost - RB26

[No Crust Racing]

Need some ideas.

 

R34 GTR.

 

Car had 354rwkw with -9s at 24psi on e85. N1 manifolds, full 3.5 exhaust with no cat.

 

Added 4bar sensor and kelford L182-A 264 cams and BC springs.

 

Car is making less power than before and is laggier to make boost everywhere.

 

345rwkw or so on 19psi and will not make anymore boost, solenoid is max duty. I knew max boost would come down but not that much.

 

Spikes to 25psi midrange but once the engine starts to breath it just falls away.

 

Have tried lots of adjustment of cam timing, bench test wastegate actuators, and checked all the connections.

 

I'm gonna go over and boost leak test it with him again and I considered bypassing BOVs for testing. I'm also going to remove intakes and inspect Comp wheels and free play.

 

Given I'm sure I could hear a new turbo bearing/whistle type sound when it comes on boost, is this symptomatic of failing turbo bearing?

 

The car had 2 boost leaks previously and I did a track day not knowing it had those leaks, worried I've cooked a turbo bearing?

 

Other ideas welcome.

 

Yes I know I should have put a single on it.

 

 

[r32-25t]

[No Crust Racing]

I should add, it had this lag and power loss issue before the cams went in.

 

This was one of the things we were chasing with this visit.

 

Just before your get on your horse

 

 

[Piggaz]

Does it idle good?

[No Crust Racing]

Yes it idles perfectly as I also suspected that maybe the timing had been thrown out. He said it is revving cleanly it is just a boost issue.

 

And if you remember from my build thread I was chasing a boost leak and that whistling sound before the cams went in.

 

Would stuffed blow off valves have this kind of effect? Or does the vented pressure just end up back in the intake anyway and have no bearing on Max boost?

 

 

[djvoodoo]

A symptom of a cooked turbo bearing would be grey/white smoke yea?

[No Crust Racing]

If it's an oil seal yeah I guess?

I'm talking more about bearing wear/pending failure.

I can hear a whistle/whirring that wasn't there previously.

Sounds like the whistle a turbo diesel 4wd makes as they spool.

[89CAL]

Have you checked end-float and side play on the turbo shafts?

[No Crust Racing]

They only had 7k on them when purchased and play was fine then, they have only done another 1000ks since.

 

I will check them again tomorrow.

 

My thought was that running a track day with a boost leak may have had them working too hard and caused an issue.

 

What would I see from faulty BOVs?

 

 

[KiwiRS4T]

Test for boost leaks by blocking off the pipe (do you have 2 into 1?) and installing a tyre valve. Apply pressure - first up to 30 psi and then 40 psi and you will see if there is a leak. What kind of wastegate and what spring are you using?

[No Crust Racing]

Do you mean testing the BOVs?

All piping to an from BOVs is factory.

These are standard garret actuators that come on -9s so I think they are 1bar.

They were both bench tested fine.

If the BOVs were leaking I would've thought it wouldn't make 25psi in the midrange?

[No Crust Racing]

Dose Pipe suggested actuators. 

I think they are the standard 15.6psi ones that ship with those turbos. Tuner bench tested them, they both crack at 17psi, is that too early for a target boost of 24ish? 

They "were" working fine.

This was them at purchase, those are the actuators. 

I will test BOVs, actuators preload, and shaft play tomorrow. 

Anything else? 
 

[KiwiRS4T]

My suggestion for pressure testing was for the whole induction system - not just the bovs - also the piping, intercooler - all the connectors.

I take it your boost control is by an aftermarket ECU and Mac valve. When you say the solenoid is at max duty - that should mean fully closed so no boost should be getting to the actuators...are you sure you have that right? I forgot you were using IWG. Maybe you need some heavier duty actuators such as the HKS ones.

[No Crust Racing]

I had pressure tested the entire intake previously when chasing boost leaks, up to 40psi. Will do it again to be sure.

 

One thing a static test doesn't show is BOV leakage as anything going past is still in the same pipework, I'm just not sure what the symptoms are with faulty BOVs when the leak is past the seat and recirculating back into the intake.

 

Haltech with 4bar sensor and Mac solenoid.

 

If need be I'll wire the actuator flap shut to test it.

 

 

 

 

[fatz]

Gasket leak btw engine and tubos

[No Crust Racing]

Intake gasket is new, new gaskets on exhaust manifold and turbos.

 

Should also show on boost leak test?

 

 

[No Crust Racing]

Found main issue, failed turbo.

Thanks for the suggestions.

[Piggaz]

What's the plan now?

[No Crust Racing]

Considering I recently herniated a disc in my back and had a vasectomy on Friday, not much until I recover a bit.

 

Leave it here.

 

Get prices on options.

 

Try not to rage?

 

 

[Piggaz]

Was it the rear snail that died?